This invention relates generally to drink dispensers, including nursing bottles for infants. More specifically, the present invention relates to drink dispensers which incorporate a collapsible plastic bag to hold a fluid in the dispenser, and a means for expelling air from the collapsible bag so that only the liquid remains for drinking. Moreover, the present invention relates to an improved mouthpiece or nipple to facilitate suction withdrawal of liquid from the drink dispenser.
Nursing bottles for infants are generally known in the art and typically comprise a resilient nipple mounted onto a cap or neck ring which is adapted in turn for mounting onto a bottle containing a selected beverage or food product in liquid form for an infant. The resilient nipple comprises a soft and collapsible mouthpiece which is manipulated by the infant with an alternating collapsing and expansion motion in combination with a sucking action to draw the liquid contents of the bottle through a nipple port. Nursing bottles of this standard type must be held in an inverted or substantially inverted position during use, to ensure fluid flow communication of the bottle contents to the resilient nipple. Further, such conventional bottles naturally fill with air as the infant drinks the liquid. In turn, the feeding infant tends to swallow some of the air, causing indigestion.
As an improvement on this long existing configuration, a newer generation of baby nursing bottles consists of a polymeric cylinder into which a collapsible plastic bag can be positioned. The plastic bag is usually secured at the top of the cylinder by a neck ring or the like. The milk, formula or other liquid is then added to the bag rather than to the cylinder or bottle itself. When topped with the appropriate nipple assembly, this arrangement desirably provides a system under which the bag gradually collapses as the infant feeds from the liquid therein. Because the bag collapses, there is a lesser tendency for air to enter the bottle as an infant drinks. Ideally, this system helps an infant to swallow less air during feeding than the infant would when feeding from a noncollapsible bottle.
Nevertheless, an air content problem remains with such collapsible bag feeding systems in that during normal filling procedures the collapsible bag cannot be filled completely with liquid. In this regard, such baby nursing bottles initially require that air in the chamber formed by the nipple and the liner cavity be expelled manually prior to the start of feeding. One typical and common method of expelling air is for the user to insert his or her fingers into an open end of a shell body and push on the liner until all of the air is expelled and only liquid remains. While air may be expelled in this manner for a full bottle, as the amount of liquid in the bottle diminishes the liner must be pushed further into the shell from the open lower end of the shell body until the user's fingers can no longer reach the liner to compress the liner and liquid contained therein to expel any captured air.
Bottles have been devised to incorporate mechanical assisting means to force air out of the bottle by physically moving the plastic bag towards the mouthpiece. Such a device is the subject of Holmes, III (U.S. Pat. No. 5,078,287) which utilizes a lower rigid support which is manually slid into the cylinder to force the plastic bag upward. However, the parent must constantly attend to and push the rigid support upward to expel air from the bottle.
The presently used newer generation bottles require that the bottle be in an inverted and nearly vertical position in order to effectively remove the fluid. The liners of most bottles are placed over the neck of the bottle with a ring or cap holding the liner in place. Due to this configuration as well as the flexibility of the liner, the natural tendency of the liner is to collapse upon itself along its longitudinal axis instead of moving upward towards the nipple. Thus, as the fluid is removed from such bottles the flexible liner collapses or flattens upon itself along its longitudinal axis and increasingly narrows the space available for fluid to flow to the nipple. Increasing suction is required to provide an ever decreasing fluid flow.
Due to the natural inclination of the liner to collapse upon itself and constrict fluid flow, the child cannot suck fluid from the bottle while in a vertically erect or standing position. This is an ever increasing concern as the child grows and matures and desires to feed from the bottle in a sitting or standing position. In order to provide a constant fluid flow, the child must horizontally recline or arch his or her neck and back to force the fluid towards the nipple of the inverted bottle. However, even in an inverted position, small pockets of fluid can still be formed within the flattening liner and require a great deal of suction to remove.
The nursing bottles of Phlapahongaphanich (U.S. Pat. No. 4,815,615) and Barton (U.S. Pat. No. 2,876,113) are the only bottles that the inventor is aware of that do not attach the plastic bag over the neck of the bottle. This provides these bottles a degree of liner upward mobility not found with other bottles. However, these devices do not provide sufficient space above the bag to fully accommodate the collapsing bag and thus suffer from the same drawbacks of other newer generation nursing bottles in that the bag collapses longitudinally as previously discussed.
Morever, these nursing bottles allow air to enter into the liner after the bottle has been put aside, particularly in an upright position such as might be the case when the baby is being burped or otherwise attended to. The weight of the liquid in the liner tends to pull the liner downward drawing air into the liner through the nipple. Air may also be drawn into the liner through the nipple or cap when the baby stops sucking for a period of time. Once the bottle is inverted and the infant begins feeding again, the air travels through the liquid and is trapped in a pocket at the top of the inverted bottle. As the fluid is removed, the air pocket remains at the top of the inverted bottle and can be nearly closed off by the liner as the fluid is removed. If the infant continues to suck after the fluid is removed, air is drawn through the nipple and into the infant causing indigestion.
Due to the formation of the air-pocket and flattening of the liner of the bottles of Phlapahongaphanich and Barton, the liner ceases collapsing at or near the point where it is attached to the rigid part of the bottle. The liquid from the nipple to the end of the liner cannot be sucked out of these bottles due to insufficient force, or inadequate vacuum, to fully draw the liner inversely towards the nipple as well as the failure of the liner to fully travel inversely towards the nipple.
Bottles have been devised with a valve incorporated into or otherwise associated with the nipple, such as the bottle of Yamauchi (U.S. Pat. No. 3,651,973). The valve is intended to overcome the problems which are brought about when air enters the bottle. However, Yamauchi has no rigid guide for the liner and as fluid is removed the liner collapses upon itself to create a constriction between portions of the fluid. This is particularly the case if the child sucks when the bottle is not completely inverted. Even in a reclined position, the child must apply a great deal of suction to remove the lower portion of the fluid through the liner constriction and towards the nipple. Due to the constriction and fluid pouch formation due to gravity, the liner cannot fully travel inversely to completely remove the liquid from the bottle. To overcome the longitudinal collapse and constricted fluid flow of the liner, Yamauchi incorporates a sliding lower section which is pushed against the liner to force the fluid upward. While effectively forcing the fluid into contact with the nipple, use of the sliding sections has the same disadvantages as Holmes III in that the parent must periodically push the section upward to avoid constrictions and provide fluid flow.
Further, a variety of modified nursing bottles have been proposed to include a length of flexible tubing extending between the bottle and the nursing nipple. The flexible tubing effectively spaces the nipple from the bottle, with a view toward permitting consumption of the bottle contents without requiring the bottle to be held by the infant or by an adult. In some instances, the tubing terminates at the bottle cap and thus requires support means of some type for retaining the bottle in an inverted position during use. In other designs, the tubing extends through the bottle cap to a position near the bottom of the bottle, and it is intended that the bottle contents be withdrawn by suction while the bottle remains in an upright position.
It has been discovered that conventional nursing nipples of a soft and collapsible construction are generally unsatisfactory for use in nursing bottles of the type having an elongated suction delivery tube connected between the nipple and the interior of the bottle. That is, as the resilient nipple is alternately collapsed and expanded in such bottle designs, the liquid within the bottle is primarily displaced back and forth within the delivery tube, with a minimal quantity of the liquid reaching the infant for consumption. It is believed that the natural inclination of the infant to the collapse and expand the nipple sufficiently disrupts the suction action applied to the delivery tube, whereby little liquid actually reaches the infant in the absence of a significantly increased suction.
In summary, prior drinking dispensers which incorporate a collapsible plastic bag or flexible liner, while presenting numerous advantages over prior nursing bottles, still have disadvantages in their design which require attention. When the drink dispenser is in an upright position and liquid is in the lower part of the flexible/collapsible bag or liner, the upper part of the liner tends to constrict in diameter making it harder to suck liquid out of the bag. Further, as the plastic collapses, it is difficult to tell how much liquid is left in the fluid dispenser or bottle.
Accordingly, there is a need for a simple, straightforward device and drink dispenser construction that permits all of the air to be expelled from the flexible liner and which overcomes the drawbacks noted above. In particular, a fluid dispenser is needed which permits a user to clearly ascertain how much liquid remains in the dispenser (permitting, by easy calculation, how much has been consumed). Moreover, a novel drink dispenser is needed which permits air to be easily expelled from the liner, accommodates pre-filled liners to be sold as a unit with the surrounding dispenser, and allows the user to suck liquid easily and smoothly with the drink dispenser in virtually any orientation. With regard to nursing bottles, a need exists for a fluid dispenser having an elongated flow or delivery tube to accommodate versatile bottle positioning relative to a resilient nipple member, while insuring substantial liquid flow of the liquid to the infant in response to a normal suction action. Such an elongated delivery tube will preferably have approximately the same length as the flexible liner. What is still further needed is a nursing bottle which allows the infant to feed from any angle or position, including an upright standing position. The present invention fulfills these needs and provides other related advantages.